NO. 1205. SYNOPSIS OF THE NAIADES— SIMPSON. 611 



sisting of four or five heavy, parallel ridges, which fall low in front but 

 are curved upward behind; epidermis smooth, generally shining, 

 painted with numerous delicate, wavy, darker, broken rays; pseudo- 

 cardinals strong, direct, and ragged; laterals short, nearly straight; 

 anterior muscle scars small, the sides of the pit smooth, the bottom 

 ragged; front part of the shell very solid, suddenly becoming rather 

 thin just behind the knobs; male and female shells essentially alike. 

 Animal with small branchiae, rounded below, inner the larger, free 

 from the abdominal sac in part ; marsupiura consisting of a few distinctly 

 marked ovisacs (4 to 7), occupying a position just behind the center 

 of the outer gills, projecting far below the rest of the branchiae, their 

 bases rounded; mantle cut away at the thinner portion of the shell; 

 anal opening smooth or having only minute crenulations. 



fOBLIQUARIA REFLEXA Rafinesque. 



* OMiquaria (Quadrula) reflexa Rafinesque, Ann. Gen. Sci. Phys., 1820, p. 306. — 



* Chenu, Bib. Conch., 1st Ser., Ill, 1845, p. 19. 



* Obliquaria reflexa Baker, Moll. Chicago, Pt. 1, 1898, p. 89, pi. xiv, fig. 5 ; xx, fig. 2. 



* Ifnio reflexus Say, Am. Conch., No. VI, 1834.— * Conrad, New F. W. Shells, 1834, 



p. 71; *Monog., I, 1835, p. 7, pi. iv, fig. 1. — * Feuussac, Giier. Mag., 1835, p. 



28.—* KusTER, Conch. Cab. Unio, 1852, p. 52, pi. xi, fig. 2. — " Conrad, Pr. Ac. 



N. Sci. Phila., VI, 1853, p. 256.—* Reeve, Conch. Icon., XVI, 1864, pi. vi, fig. 23. 



*Unio cormitus Barnes,' Am. ,11. Sci., VI, 1823, p. 122, pi. iv, figs. 5, 5a, 51), 5c, — 



* ?Anton, Verz. der Conch., 1839, p. 14.—* Hanley, Test. Moll., 1842, p. 179; 

 Biv. Shells, 1843, p. 179, pi. xx, fig. 30. — * Catlow and Reeve, Conch. Nom., 

 1845, p. 57. — * H. and A. Adams, Gen. Rec. Moll., II, 1857, p. 497. — * Calkins, 

 Pr Ottawa Ac. N. Sci., 1874, p. 41.—* B. H. Wright, Check List, 1888. 



*Margarita ( Unio) cornutus Lea, Syn., 1836, p. 15 ; 1838, p. 15. 

 *Margaro7i {Unio) cornutus Li^A, Syn., 1852, p. 22; 1870, p. 33. 

 *Mya cornuta Eaton, Zool. Text-book, 1826, p. 216. 

 ^ Theliderma cornuta Swainson, Treat, on Mai., 1840, p. 269. 

 Unio torulosus Short and Eaton, Transylvania Jl., 1831, p. 75. 

 *t? Unio phili2)2)si Conrad,^ Monog., I, 1835, p. 9, pi. v, fig. 1; *Pr. Ac. N. Sci. 

 Phila., VI, 1853, p.255.— * P^.tel, Conch. Sam., Ill, 1890, p. 163. 



* Unio philUpsii Catlow and Reeve, Conch. Nom. , 1845, p. 62. — * Kuster, Conch. 



Cab. Unio, 1852, p. 50, pi. x, fig. 3.—* H. and A. Adams, Gen. Rec. Moll., II, 

 1857, p. 497.— *B. H. Wright, Check List, 1888. 



* Margarita {Unio) pliillipsii Lea, Syn., 1836, p. 15; 1838, p. 15. 

 "^Margaron { Unio) pliillipsii Lea, Syn., 1852, p. 22; 1870, p. 33. 



* Unio philipsii Hanley, Test. Moll., 1842, p. 178; Biv. Shells, 1843, p. 178. 



Mississippi drainage; Michigan; Alabama River; southwestwardly 

 to central Texas. 



' I am sorry to have to place the very appropriate and well-known name of Barnes 

 in the synonymy, but I believe that the description of Rafinesque for his Obliquaria 

 reflexa defines this species and nothing else, and although it is not figured, I feel jus- 

 tified in using it. 



2 A singular shell having the general form of reflexa, but the knobs are much 

 broken up. I have seen specimens which agree quite well with Conrad's fine figure, 

 which I have no doubt represents an unusual form of Raflnesque's species, and they 

 hardly seem to me to be a varity. I do not think the so-called type in the Phila- 

 delphia Academy of Natural Sciences is valid. 



